1. Field of the Invention
The present disclosure relates to graphic memories, and more particularly, to a method and apparatus for controlling the operation of writing data to a graphic memory.
2. Discussion of the Related Art
A liquid crystal display (LCD) driver integrated circuit (IC), which is generally used in mobile devices, drives a display operation according to a clock signal, an enable signal, and data which are asynchronously transmitted from an external host. Commands and display data received via such an asynchronous interface are written in real time to a graphic memory included in a driver IC, and are transmitted to a source driver and to a gate driver in synchronization with a regular display timing, thereby driving an LCD.
Since the demand for high-quality moving pictures has recently increased, a faster update of graphic memory with display data is needed. However, the conventional method of writing data to a graphic memory does not satisfy such a need.
FIG. 1 is a conceptual diagram of a conventional method of writing data to a graphic memory, that is, accessing the graphic memory. In the conventional graphic memory accessing method, data[23:0] is a string of data pieces sequentially written to a predetermined space of the graphic memory (GRAM) in synchronization with a data input clock signal WRX. However, even with the demand for an increase in the speed at which data is written to graphic memory, the conventional method of FIG. 1 has a limit as to increasing the data writing speed because of the minimum write cycle time of the graphic memory.
In other words, in the conventional method of writing data to a graphic memory, data pieces of adjacent pixels are sequentially written to adjacent storage areas of the same graphic memory, so that data writing cannot be faster than the write cycle speed of the graphic memory itself. For example, when the speed at which 1-bit data is input is 500 Mbps, the actual data writing speed does not exceed about 20 MHz although a data writing speed of 62.5 MHz is required. In recent years, since a driver IC having a graphic memory is included even in products of quarter video graphic array (QVGA) standard or higher, for example, wide quarter video graphic array (WQVGA), half video graphic array (HVGA), or video graphic array (VGA), an increase in an operating speed of a graphic memory is needed.